Email has become an important method for communicating. Email systems typically include a server component (e.g., Microsoft Exchange™ Server) and a client component (e.g., Microsoft Outlook™ or Microsoft Outlook Express™). These components are typically software applications that are configured to execute on computing devices (e.g., servers, desktops, laptops, and mobile devices). Such email client applications allow users to draft email messages through a user interface and send the messages to recipients. Some email messages may contain files as attachments that are delivered to a recipient along with the message. An email attachment may be any file type including a spreadsheet, a word processing document, or a photograph. One or more files can be attached to a given email message. Attachments can vary in size, typically ranging from a few bytes to twenty-five megabytes.
Typically, an email client allows a user as a sender to send an email with or without an attachment to a list of recipients. Each recipient can respond by replying to the sender individually or alternatively, a recipient can also respond by replying to all of the recipients in the email thread, also referred to as an email conversation, using a reply-all option provided by the email client. Email distribution lists and “reply to all” options are powerful email tools. As has been demonstrated many times, this power sometimes results in people becoming the recipient of unwanted messages. The cost of these unwanted messages includes wasted bandwidth, undesired interruptions, and lost productivity.
For example, someone recently sent a message to a few thousand employees of a large corporation, asking for a particular presentation. Within a few minutes, several people responded with a “reply-all,” usually attaching a presentation file or two in the 5-10 MB range. Later someone asked that people not forward large attachments to the entire group; someone followed this up by suggesting some other ways to avoid sending large attachments. After a pause, another person sent the entire list a note pointing out he would not reply-to-all with a presentation, but he still replied to all with the news that he would not send one.
While it was not the worst “reply-all storm” in terms of the number of messages, the product of the per-person data and the number of recipients is huge. It is estimated about 100 GB of traffic was sent in the space of an hour. In addition, each of the thousands of employees was alerted in some fashion about each incoming mail. While reading and deleting the messages is not onerous, some fraction of recipients undoubtedly got an email delivery alert specific to each of these messages. There is a lot of people to interrupt 5-10 times in the space of an hour or two over something which had little to no effect on their work. Further some of the recipients in the email thread may not be interested in receiving further emails on a topic which does not concern them. Such a large scale of email traffic and a large amount of data exchanged over a network can cause an unpleasant experience and unproductive working environment.
Some mail interfaces offer a “mute” or “ignore” option. For example in Gmail™ this means that a message with the same subject goes into “all mail” but bypasses the inbox for a period of time. However such messages cause certain interruption to a user until the user explicitly mutes, and the ignored or muted messages would be sent over the network. A conventional email system includes a feature of displaying a small message indicating a number of recipients of a particular outgoing email. However, such a message is typically displayed briefly and less likely catches a sender's attention. The sender can either ignore it or completely misses the displayed message. The message is displayed only based on the number of recipients and it does not take into the account of the size of the outgoing email.